[A83] Re: NMI
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[A83] Re: NMI
When the calc turns off, the display is shut off, then the calc goes into
low power mode while waiting for an interrupt. The CPU is never actually
shut off. The on key generates an interrupt, which causes a jump to the 38h
interrupt handler. When the calc is first powered on from a no power state
(the only time it is truely powered on), it starts at 00h. It is likely
that there are some variables that it reads to determine if it is necessary
to reset the memory when it is first started. It must do this, or the
lithium battery that saves the ram would be useless.
> Of course it turns off. But how? Normally the TIOS handles
> the "off" state, which is performed with setting some
> values to something else I presume. When you take out the
> batteries while "on", it is like a reset without the normal
> software shutdown process. How does the TIOS overcome the
> problems arising from such an extraordinary event?
>
> Or the "off" state is not indicated in the RAM, only
> through ports?
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